Extended Forecast Discussion NWS Weather Prediction Center College Park MD 213 AM EST Fri Feb 14 2020 Valid 12Z Mon Feb 17 2020 - 12Z Fri Feb 21 2020 ...Guidance/Predictability Assessment... Model and ensemble forecast variability remains less than stellar aloft through medium range time scales, but actually offers much better continuity with surface feature evolutions and precipitation coverage. The WPC medium range product suite was primarily derived from a blend of the GFS/ECMWF and GEFS/NAEFS/ECMWF ensemble means along with the National Blend of Models. This composite solution acts to mitigate the less predictable timing/emphasis variance aloft without sacrificing lower atmospheric detail and weather focus as consistent with predictability. ...Weather Pattern and Hazard Highlights... A series of impulses digging to the lee of a eastern Pacific upper ridge will reinforce a weatern U.S. mid-upper level trough position and surface cold frontal passages into early next week to favor cold flow with swaths of moderate precipitation including a threat of heavy terrain enhanced snows from the Pacific Northwest inland across the Great Basin/Rockies. Less certain mid-upper level trough energies will progress downstream over the Plains to spawn cyclogenesis and frontogenesis along with an emerging lead threat of widspread precipitation with warm sector rains and snow/ice on the northern periphery across the Midwest/Great lakes/Northeast with advent of southeastward surging post-frontal arctic air. The main wavy front is expected to consolidate and push out across the central and eastern U.S. Tue/Wed. While this will act to push lead moderate precipitation into the western Atlantic by midweek, expect lingering focus will remain along a trailing frontal zone back across the southern U.S. tier into later next week as additional impusles progress over the region. This may include some threat of overrunning wintry precipitation into the cold post-frontal airmass from the southern Rockies/Plains and South to the southern Appalachians/Mid-Atlantic. Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml